Question

I know the title is confusing so I’ll try to explain better. Here’s basically what I want to do inside a method:

if (record["id"] != DBNull.Value) _id = Convert.ToInt32(record["id"]);
else id = -1;

I want this to work for multiple types that I have stored in my database. (So if it’s a string it converts it to a string and so forth). Any way to do this is fine, and I was trying to do it with a method. I got this far but C# won’t automatically convert int to object. ideas?

    private void Load(ref object var, object obj, object def)
    {
        if (var is int)
        {
            var = Convert.ToInt32(obj);
        }
    }

   int _id;
   Load(ref _id, record["id"], -1);

Just to clarify, my error is “cannot convert from ref int to ref object”.
Thanks for any help.

Answer 1

You can use Convert.ChangeType() and make your method generic:

private void Load<T, U>(out T value, U obj, T defaultValue)
{
    if (obj is DBNull)
       value = defaultValue;
    else
        value = (T)Convert.ChangeType(obj, typeof(T));
}

Now you can just use it like this (simplified example, not sure what you need def for):

int id;
object foo = 42;
Load(out id, foo, 1);